Niemann-Pick disease is a group of inherited disorders belonging to the larger family of metabolic disorders called ‘lysosomal storage diseases’, in which fats accumulate within lysosomes (parts of the body’s cells that break down nutrients and other materials).

In Niemann-Pick disease type C, there is a lack of transporter proteins that are needed to move fatty substances such as cholesterol and other fats within cells, leading to the build-up of these fats in the brain and elsewhere in the body (such as the spleen and liver). This causes a wide range of symptoms, including behavioural problems, learning disabilities and difficulty moving and speaking.

Niemann-Pick disease type C is chronically debilitating and life threatening since the build-up of fatty substances can cause brain damage and swelling of organs such as the spleen and the liver.

At the time of designation, Niemann-Pick disease type C affected approximately 0.1 in 10,000 people in the European Union (EU). This was equivalent to a total of around 5,000 people*, and is below the ceiling for orphan designation, which is 5 people in 10,000. This isbased on the information provided by the sponsor and the knowledge of the Committee for Orphan Medicinal Products (COMP).

*Disclaimer: For the purpose of the designation, the number of patients affected by the condition is estimated and assessed on the basis of data from the European Union (EU 28), Norway, Iceland and Liechtenstein. This represents a population of 511,100,000 (Eurostat 2014).

At the time of designation, Zavesca (miglustat) was authorised in the EU to treat Niemann-Pick disease, type C.

The sponsor has provided sufficient information to show that arimoclomol citrate might be of significant benefit for patients with Niemann-Pick disease type C because it works in a different way to miglustat and experimental studies suggest it might be of benefit in reducing the symptoms of the disease.This assumption will need to be confirmed at the time of marketing authorisation, in order to maintain the orphan status.

In Niemann-Pick disease type C the build-up of fatty substances in the lysosomes reduces their ability to function normally and makes the membrane around the lysosome unstable. Arimoclomol is a medicine that stimulates the cell’s natural mechanisms for coping with damage, by increasing the production of proteins called heat shock proteins in cells that are under stress. These proteins help to stabilise the membrane around the lysosomes and improve the ability of the lysosome to function and break down certain fats. This is expected to help reduce the symptoms of the disease.

the existence of alternative methods of diagnosis, prevention or treatment;

either the rarity of the condition (affecting not more than 5 in 10,000 people in the EU) or insufficient returns on investment.

Designated orphan medicinal products are products that are still under investigation and are considered for orphan designation on the basis of potential activity. An orphan designation is not a marketing authorisation. As a consequence, demonstration of quality, safety and efficacy is necessary before a product can be granted a marketing authorisation.